Breech bolt lock



Sept. 11, 1962 W-. H. B. SMITH BREECH BOLT LOCK 3 Sheets-Sheet 1 Filed Deo. 2. 1959 Sept 11, 1962 w. H. B. SMITH 3,053,002

' BREECH BOLT Locx Filed Dec. 2. 1959 5 Sheets-Sheet 2 Fig. 4

INV EN TOR. WA LTA-H H. 5. .su/1H, 0555/155 ATTORNEYS.

Sept. l1, 1962 w. H. B. SMITH BREECH BOLT Locx 3 Sheeis-Sheet 5 Filed Dec. 2. 1959 INVENTOR. WALTER his. sM/TH, aisle-'A550 7 KA r//ER//vf s. @no vrs, 5X5 :zu rmx www m .www www N@ NQN NN.. QQN mGN NNN N\ @me $m e ATTORNEYS.

United States Filed Dec. 2, 1959, Ser. No. 856,752 23 Claims. (Cl. 42-16) This invention relates in general to firearms and more particularly relates to improvements in bolt-action lirearms of the rim-lire type.

Bolt-action firearms, particularly within the lowerpriced brackets, are commonly actuated by rotating the bolt, sliding it to the rear to reject the empty cartridge case, sliding it forward after a new cartridge has been inserted either manually or automatically, and again rotating the bolt to lock the bolt in position.

It is a primary object of the present invention to provide an improved bolt action of the foregoing type in which the rotation is eliminated.

It is another object of the invention to provide an irnproved bolt action in which rotation is eliminated in such a manner that the action may be utilized in low-cost firearms.

It is yet another object of the present invention to provide an improved bolt action for single shot and for semi-automatic, bolt-action rifles in which rotation of the bolt is eliminated in such a manner that the action may be utilized in low-cost firearms.

These and further objects and advantages of the invention will become more apparent upon reference to the following specification and claims and appended drawings wherein:

FIGURE l is a partial plan view of a rifle constructed according to one embodiment of the present invention;

FIGURE 2 is a vertical section of the rifle of FIGURE 1 taken along the line 2 2;

FIGURE 3 is a partial-horizontal section of the rifle shown in FIGURES l and 2 and taken along the line 3 3 of FIGURE 2;

FIGURE 4 is a vertical view partly in section, showing a modification of a bolt action constructed according to the invention;

FIGURE 5 is a vertical View, partly in cross-section, illustrating a still further embodiment of the rifle of the present invention, which embodiment is specifically adapted yfor semi-automatic action;

FIGURE 6 is a perspective view in elevation of the receiver with the bolt removed; and

FIGURES 7 and 8 are front and bottom views, respectively, of the bolt of this embodiment of the invention.

Referring to FIGURES 1 3 of the drawings, the firearm shown is a rifle of the rim-fire bolt-action type comprising a barrel 10 and integral receiver 12 having a bolt assembly 14 received therein. The barrel and receiver are mounted in a conventional manner upon a stock 14 by means of a screw 16. A suitable rear sight V18 and safety 20 are provided, although these form no part of the present invention.

The receiver 12 is apertured at 22 to provide a shellejection opening and has its rear end plugged by means of a plug 24 which is secured in position by means of a pin 26. The plug 24 has a reduced diameter portion 28 fitting within the rear end of receiver 12 and' a knurled outer end 30. The plug is bored as shown at 32.

The bolt assembly 14 consists of a cylindrical bolt 34 which is slotted at 36 to receive an extractor 38. The extractor 38 is fastened to the bolt by means of a screw 46 and has an extractor finger 42 at its forward end which fits into a mating recess in the barrel 10. A firing pin bore 44 in the lower half of the bolt 34 carries a firing fire pin 46. The firing pin 46 has a reduced diameter forward end 48 which is adapted to pass through a bore 50 to strike the rim of a cartridge chambered in the firearm. The bolt 34 is also provided with a vertical slot 52 at its bottom and this slot communicates with the firing pin bore 44 as shown at 54. A longitudinal extension 56 depends from the underside of the firing pin 46 and is slidably received in the slot 52 in bolt 34. This arrangement locks the firing pin against rotation in the firing bore.

The rear end of bolt 34 has a reduced diameter portion 58 which is secured within a cap-like member 60 by means of a pin 62. A firing pin spring 64 is compressed between the rear end of firing pin y46 and this cap-like member 60 to urge the firing pin forward.

A trigger shown generally at 66 is attached to the tirearm and has a rectangular shaped upper forward end 68 connected to a horizontal lever 70 by means of a stepped portion 72. The trigger is fastened to the barrel by means of a leaf type trigger spring 74 and screw 76. The rear end of the spring 74 has a pair of vertical ears 78 which are pinned to the rectangular upper forward end 68 of the trigger by a pin 80. A scar 82 is mounted on top of the spring 74 at the rear end thereof and passes through an aperture 84 in the receiver 12. The sear 82 is flat and has a diagonal forward edge 86. The rear end of the sear is cut away at 88, so that when the firearm is in the cocked position, this cutaway portion of the sear engages the forward edge of the extension 56 on the firing pin 46 to hold the tiring pin against the compressed ring spring 64.

Referring most particularly to FIGURE 3, the cap 60 which is attached to the rear end of the bolt 34 has a rearward cylindrical extension which is slotted at 92 to receive the forward end of a bolt actuating cam member comprising plate 94. The plate 94 is connected to the extension 90 by means of a lost-motion connection consisting of pin 96 in extension 90 and elongated slot 98 in plate 94. The rear end of plate 94 has a downwardly projecting tab 10() thereon, and this passes through a slot 102 at the bottom of a receiver. A bolt actuating ring 104 slides on the outside of the receiver and is connected to the tab at 106. The actuating ring 104 has ears 108 thereon for convenient gripping for moving the bolt to the rear.

Referring to FIGURE 2, a breech bolt lock assembly 109 depends from the underside of the receiver and consists of a breech bolt lock housing comprising cylinder 110 brazed or otherwise secured to the receiver. A breech bolt lock 112 is slidably mounted therein. The breech bolt lock 112 consists of a cylindrical lower portion 114 having an internal bore 116 and having a reduced diameter upper end 118. The reduced diameter end 11S passes through an aperture 120 in the underside of the receiver and the forward face of the reduced diameter portion 118 is cut away at 122 for a purpose presently to become apparent. The breech bolt lock 112 is forced upwardly by means of a coil spring 124 mounted within the internal bore 116 in the breech bolt lock cylinder and bearing downwardly on a pin 126. The lower cylindrical portion 114 of breech bolt lock 112 is slotted at 128 to receive the pin 126 and permit downward move-r ment of the breech bolt lock against the compression of the spring 124.

The forward surface of the lower end of the breech bolt lock cylinder 110 is slotted `at 130, so that the ystepped portion 72 of trigger 66 may enter the slot to permit movement of the trigger. In the position shown in FIGURES 2 and 3, the firearm is in a cocked position ready to flre and the rear faces 132 (FIGURE 3) of the extension 90 of cap 60 butt against the cutaway portion 122 of the reduced diameter upper end 118 of the breech bolt lock 112. The plate 94 is cut away over the breech bolt lock at 133 and this cutaway portion is shaped to provide a rectangular rear edge 134 and a downwardly diagonal forward edge 136 with edge 136 forming a cam for breech bolt lock 133.

The operation of the rearm will now be described starting with the cocked condition shown in FIGURE 2. In order to fire the firearm the trigger 66 is pulled to the rear and the trigger pivots about the rear corner of the rectangular forward section 68 until the stepped portion 72 engages the bottom of the lower cylindrical portion 114 of breech bolt lock 112.

This lowers the rear end of the spring 74 so that the sear 82 is pulled out of engagement with the longitudinal extension 56 depending from the firing pin 46. When fthe sear clears this extension the ring spring 64 drives the firing pin forward so that its reduced diameter portion 48 strikes the rim of a cartridge to re it. The bolt is at this time locked in position by means of the breech bolt lock whose cutaway portion 122 engages the rear faces 132 of the bolt assembly.

In order to reject the spent cartridge the ears 108 of the actuating ring 104 are pulled to the rear. This causes plate 94 to move rearwardly so that the diagonal edge of cutaway portion 133 cams the breech bolt lock downwardly against the resistance of spring 124. The bottom edge of the cylindrical lower portion 114 of breech bolt lock 112 strikes the `stepped portion 72 of trigger 66 to return it to a ycocked position. This also prevents actuation of the trigger except when the breech bolt lock is in a breech locking condition. When the reduced diameter portion of the breech bolt lock is cammed ush with the surface of the bore in the receiver, the pin 96 in extension 90 strike the forward end of slot 98 so that further rearward movement of ears 108 and plate 94 carries the bolt 34 to the rear. The bolt 34 maintains the breech bolt lock in a depressed position. As the plate 94 approaches its rearwardmost position, which is determined bythe plug 24, the longitudinal extension 56 depending from the ring pin 46 cams the sear 82 downwardly until it passes thereover. The resiliency of spring 74 then causes the sear to spring upward into locking engagement with the extension 56. The extractor 38 has in the meantime extracted the spent cartridge casing which may be removed from the receiver and a new cartridge inserted.

The bolt assembly is then forced forward by means of the ears 108 and, as this is done, the firing pin 46 is held by the sear 82, so as to again compress the firing spring 64 to cock the firearm. The reduced diameter portion 118 of the breech bolt lock 112 is snapped into breech blocking position by Ispring 124 as soon as the rear faces 132 of extension 90 pass over the cutaway edge 122 of the breech bolt lock. The rearm is then in a cocked position ready for ring.

Referring to FIGURE 4, there is rshown another embodiment of the invention wherein the -actuating ring 104 is dispensed with. In this embodiment the rearm construction -is similar t that of FIGURES 1-3 except that the plate 94 is connected to a cylindrical member 138 having la reduced diameter section 140 pinned to the plug 24 by means of pin 142. In this case, however, the pin 142 does not pass through the receiver, so that the plug 24 and cylindrical member 138 are slidable within the receiver. The slot 102 in the bottom of the receiver terminates at 144 and a Iscrew 143 is screwed into the forward end of the cylindrical member 138 and slides in slot 102. The operation of this embodiment of the invention is the same as that shown in FIGURES 1 3 except that the bolt is here actuated by grasping the plug 24 and pulling it to the rear in order to eject the spent cartridge and insert a new cartridge. The rearward motion of the block assembly is limited by the screw 143 engaging the rear edge 144 of `slot 102.

Referring specifically to FIGURES through 8 of the accompanying drawings, there is illustrated a further embodiment of the invention which is adapted for semiautomatic action although this embodiment of the invention may be utilized as a single shot mechanism if the clip required for semiautomatic action is removed. The firearm includes a barrel 10 and a receiver 12 closed off by a cap 24a secured to the receiver by pin 26a. In this emobdirnent of the invention, the wall of the receiver 12, which denes the bottom 4of the aperture 22 in the receiver, is iteslf apertured as at 146. The aperture 146 communicates with the interior of a clip holder 148 secured to the outer lower surface of the bottom wall of the receiver 12. The clip holder 148 is provided with a clip hook 150, which is pivoted between lobes 152, only one of which is illustrated, that extend rearwardly from the clip holder 148. The member 150 is biased by a spring 154 so that its lower extremity which defines a forwardly extending hook 156 is disposed below the opening in the clip holder 148 and is adapted to engage the lower surface of a clip in order to retain it in the clip holder 148 and in operating position with respect to the rie.

In order to provide the space required for the clip holder 148, the trigger assembly illustrated in FIGURES 1 through 3 and FIGURE 4 must be modified since the clip holder 148 occupies the position of the spring 74 in these prior embodiments. In order to support the trigger designated by the reference numeral 158, the breech bolt lock assembly 109 is extended forwardly as `a solid body having a vertical Islot in its front surface of sufficient width `and depth to receive a rectangular portion 162 of the trigger 158. The trigger is pivoted about a pivot pin 164, extending through aligned apertures in the trigger 158 and the forward extension 160 of the breech bolt lock assembly 109. The rectangular portion 162 of the trigger has a forwardly extending arm 166, which has a vertical slot 168 formed adjacent its forward end. The forward end of the arm 166 is disposed between downwardly depending legs 170 and 172 (see FIG. 6) of a sear 174, having a generally H-shaped cross-section with its upper Isurfaces sloping forwardly and downwardly. A pivot pin 176 extends through aligned apertures in the legs 170 `and 172 of the Sear 174 and through the slot 168 in the forward end of the arm 166 of the trigger 158.

The `sear 174 extends through an aperture 180 in the bottom wall of the receiver, `and is adapted to engage a downwardly depending lug 182 on the firing pin 184. The ring pin 184 is mounted in a bolt assembly 186, consisting of a generally cylindrical bolt 188, having extractors and 192, disposed in slots 194 and 196 in diametrically opposed sides of the bolt 188. The bolt 188 has a firing pin bore 198 inthe upper portion thereof, and the firing pin 184 is disposed therein. The forward end 200 of the firing pin 184 is of reduced diameter and is adapted to pass through a bore 202, to strike the rim of the cartridge.

The bottom surface of the bolt 188 has a downwardly extending E-shaped cross-section defining a center leg or ridge 204, which is adapted to pass between upper legs 206 and 208 of the H-shaped sear 174 when the bolt is retracted for the purposes of rejecting a cartridge and cocking the trigger mechanism. In consequence the scar, in addition to its usual function, also serves as a bolt guide in conjunction with the leg 204. The downwardly depending leg 204 of the bolt terminates in a Vertical `slot 210, which communicates with the n'ng pin bore 198 in the bolt 188. The downward extension 182 of the firing pin extends through the slot 210, and is adopted to engage the back wall of the Sear 174 when the sear is biased into its uppermost position.

The sear is biased into the tiring pin engaging position land the trigger `is maintained in its return or clockwise position by means of a single piece of spring wire 212, which at its forward end is disposed in a slot 214 in Ithe leg 172 `of the sear, and at its forward end extends into a slot in the forward extension 160` of the breech bolt lock assembly 109. The spring Wire 112 passes over a stud 214, secured to the trigger, and is tensioned thereby.

When the trigger is rotated counter-clockwise, as viewed in FIGURE 5, about its pivot pin 164, the spring wire 212 is bent around the stud 214 and exerts an upward pressure on the leg 172 of the sear 174 and via the pin 168 to the trigger thereby biasing the scar into its upward position and biasing ythe trigger into `a clockwise direction, the motion being limited by contact between the upper surface of the arm 166 of the trigger 158 and the bottom surface of the receiver 12.

In this embodiment of the invention the bolt may be retracted by either of the mechanisms illustrated 1 through 3 or 4 or may be provided with a conventional bolt handle 216, which is secured by an arm 218 to the plate 94. The arm 218 extends through a longitudinally extending slot 220, on the right side of the receiver 12, the slot 220 being of sufcient length to allow the bolt to be completely retracted.

'Ihe operation of the embodiment of the invention illustrated in FIGURE 5 is now described. The apparatus is illustrated in its cock position, and when the linger portion of the trigger 158 is squeezed, the trigger is rotated clockwise about the pivot pin 164 and moves the sear 174 downwardly until the lower surface of the downward extension 182 or the ring pin is permitted to move forwardly between the blades 206 and 208 of the sear. Upon this occurrence the portion 200 of the tiring pin extends forwardly through the bore 202 and into contact with the ring rim of the bullet; the propelling force of the tiring pin being provided by a tiring pin spring 222. When it is desired to extract a shell and re-cock the piece, the bolt handle 216 is pulled rearwardly, which moves the bolt to its rearward position with the bottom leg 204 of the bolt passing between the legs of the sear and preventing rotation of the bolt. Rearward movement of the bolt extracts the shell and upon forward movement a new cartridge is wiped from out of the clip by the leg 204 and Iforced into the chamber of the lille.

It will be noted that the apparatus described with respect to FIGURES 5 and 6 is particularly adapted for use with a semi-automatic riile. However, the bolt and trigger mechanism illustrated in these gures may be utilized in the single-shot rille of the type illustrated in FIGURES 1 to 3 `and 4 and preferably would be employed fin both types of rifles so that the parts are interchangeable and the manufacturer need not stock additional parts for various models. It the bolt and trigger mechanisms illustrated -in FIGURES 5 and 6 are utilized for ya single shot model, then the only difference between the single shot and semi-automatic rie relates to the .provision of a clip.

It will be apparent from the foregoing that the firearm of the invention has a bolt which may be opened and closed by a simple reciprocating motion. This is accomplished with a type of construction which permits its adoption in low-cost firearms which provide an eiective bolt-locking action. A minimum number of moving parts are utilized and the construction is such that damage to the unit is unlikely.

'I'he invention may be embodied in other speciiic forms without departing from the spirit or essential characteristics thereof. The present embodiments `are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by United States Letters Patent is:

1. In a gun action having a receiver with a bolt slidably mounted therein, a breech bolt lock mounted on said receiver for reciprocation on an axis substantially perpendicular to the axis of sliding movement of said bolt,

a bolt locking position and out of said receiver into a bolt unlocking position, and bolt actuating means slidably mounted on and extending into said receiver, a lost motion connection, said Ilost motion connection connecting said actuating means to said bolt, said actuating means including cam means Ifor camming said breech bolt lock out of the path of said bolt as said actuating means is moved rearwardly.

2. A gun action as set out in claim l wherein said breech bolt lock is mounted for reciprocation in a. breech bolt lock housing, said housing being xably mounted on said receiver, said breech bolt lock being slidably mounted in said housing, and a spring, said spring urging said breech bolt lock into said receiver into a bolt locking position.

3. A gun action as set out in claim 2 wherein said actuating means includes a cam member and a handle portion attached to said cam member, said lost motion connection comprising said cam member being attached to said bolt by a pin and slot connection.

4. A gun action as set out in claim 3 wherein said' cam member has a cutaway portion having a rectangular rear end and a diagonal forward end.

5. A gun action as set out in claim 4 wherein said diagonal forward end of said cutatway portion is forward of the rear end of said bolt lock when said breech bolt lock is in its bolt locking position.

6. In a gun action having a receiver with a bolt slid-` ably mounted therein, a breech bolt lock mounted on said receiver for reciprocation on an axis substantially perpendicular to the axis of sliding movement of said bolt, said breech bolt lock being movable into said re` ceiver to a bolt locking position and out of said receiver into a bolt unlocking position, and bolt actuating means `slidably mounted on and extending into said receiver, a lost motion connection, said lost motion connection connecting said actuating means to said bolt, said actuating means including cam means for camming said breech bolt lock out of the path of said bolt as said actuating means is moved rearwardly, said breech bolt lock being' mounted for recipro'cation in a breech bolt lock housing, said housing being xably mounted on said receiver, said breech bolt lock being slidably mounted in said housing, and a spring, said spring urging said breech bolt lock into said receiver into a bolt locking position, said actuating means including a cam member and a handle portion attached to said cam member, said lost motion connect-ion comprising said cam member being attached to said bolt by a pin and bolt connection, said bolt having a bifurcated rear end and said cam member comprising a plate having a slot therein, said plate being received between said bifurcated portions of said bolt and secured thereto by a pin passing through s'aid slot.

7. -A gun action as set out in claim 6 wherein said plate has in its lower edge a cutaway portion with a rectangular rear end and a diagonal forward end.

8. A gun action as set out in claim 7 wherein said breech bolt lock housing is cylindrical and said breech bolt lock has a cylindrical lower end with a bore therein, said lower end of said breech bolt lock being provided with a slot therein, a pin passing through said housing and said slot, and a spring in said bore compressed between the upper end of said bore and said pin.

9. A gun action as set out in claim 8 wherein said breech bolt lock has an upper reduced diameter portion connected to said lower cylindrical portion and passing through said receiver.

i10. A gun action as set out in claim 1 wherein said bolt includes a firing pin mounted in a bore therein and urged forward by a tiring pin spring, a trigger, a trigger spring carrying a shear engageable with an extension on said ring pin, said trigger connected to said gun action solely by said trigger spring.

111. A gun action as set out in claim 1=0 wherein said said breech bolt lock being movable into said .receiver to sear is mounted on the upper surface of said trigger spring adjacent the rear end thereof and comprises a flat memlber having a diagonal front edge and a substantially vertical read edge, said extension on said tiring pin paSS- ing through a slot in the lower face of said bolt and having a vertical forward edge and a diagonal rear edge engageable with the forward edge of said sear.

`12. A gun action as set out in claim l wherein said trigger spring comprises a leaf type spring, said trigger having a forward portion with a rectangular upper end pivoted to the rear end of said trigger spring.

A13. A gun action as set out in claim 12 wherein said trigger spring is pivoted to the forward end of said forward portion and maintains the upper edge of said forward portion in engagement with the underside of said receiver.

14. A gun action as set out in claim 13 wherein said .breech bolt lock has a lower portion which engages said Itrigger when said cam means has cammed said breech ibolt lock out of the path of said bolt.

15. A gun action as set out in claim 14 wherein said breech bolt lock is mounted for reciprocation in a breech [bolt lock housing, said housing being xably mounted on said receiver, said breech bolt lock being slidably mounted in said housing, and a spring, said spring urging said breech bolt lock into said receiver into a bolt locking position.

'16. A gun action as set out in claim 15 wherein said actuating means includes a handle portion attached to said cam member, said cam member being attached to said bolt by a pin and slot connection.

117. A gun action as set out in claim 16 wherein said lbolt has a bifurcated rear end and said cam member comprises a plate having a slot therein, said plate bein-g received between the bifurcated portions of said bolt `and secured thereto by a pin through said slot.

18. A gun action as set out in claim 17 wherein said plate has in its lower edge a cutaway portion with a rectangular rear end and a diagonal forward end.

19. A gun action as set out in claim 18 wherein said bolt lock has a cylindrical lower end with a bore therein,

said lower end of said. breech. bolt lock having a slot therein, a pin passing through said housing and said slot, and a spring in said bore compressed between the upper end of said bore and said pin.

20. A gun action as set out in claim 19 wherein said bolt includes a firing pin mounted in a bore therein and having a downward extension extending through a vertical slot in said bolt, and a trigger carrying a sear engageable with said extension on said tiring pin.

l2l. In a gun action having a receiver with a bolt slidafbly mounted therein, a breech bolt lock housing mounted on said receiver, a breech bolt lock mounted for reciprocation in said housing along an axis substantially perpendicular to the axis of sliding movement of said bolt, bolt actuating means, a lost motion connection, said lost motion connection operatively connecting said actuating means with said bolt, said bolt having a ridge depending from the bottom thereof, trigger means, and a sear, said sear being carried by said trigger means and cooperating with said ridge on said bolt to guide the movement of said bolt.

22. A gun action as set out in claim 21 wherein said `sear has a pair of upstanding legs engageable with opposite sides of said ridge upon retraction of said bolt.

23. A gun action as set out in claim 21 wherein the trigger means is mounted for rotation on said housing.

References Cited in the le of this patent UNITED STATES PATENTS 1,340,943 Eickhotf et al May 25, 1920 1,425,810 Thompson Aug. 15, 1922 1,895,719 Lahti Jan, 31, 1933 l2,365,087 Lanchester Dec. 12, 1944 l2,648,153 Dicke Aug. 11, 1953 2,775,835 Gaidos Jan. 1, 1957 2,890,626 lAmsler June 16, 1959 2,922,240 Allyn Jan. 26, 1960 FOREIGN PATENTS 593,045 Germany Feb. 20, 1934 

